The research explored how the concepts of sustainability and equity can be applied to improve municipal sanitation services in South African informal settlements and to explore various dimensions of sustainability and equity in relation to sanitation. The dimensions of sustainability considered were: economic, social (with health highlighted), technical, environmental and institutional. The dimensions of equity defined in the research included: access, resource allocation and perceptions. A comparative case study method using the lens of sustainability and equity was used to critique the approaches to providing sanitation services to informal settlements in three of South Africa’s largest municipalities: eThekwini (Durban), Johannesburg and Cape Town. Each municipal case study incorporated an embedded case study that was used to examine sanitation services in selected informal settlements at a program, project or settlement level. Primary data was collected using interviews and field visits. Secondary data was obtained from national and municipal records such as water and sanitation department reports, census data from Statistics South Africa, and municipal geographical information system databases. Findings from the research indicate that there is a need to better incorporate multiple stakeholders’ perspectives on what sustainable and equitable sanitation services should be like. Strengths and weaknesses of each municipality’s approach to sanitation service provision were compared and used to identify factors relating to successes or failures in sanitation service provision to informal settlements. A major conceptual gap identified in sanitation service delivery approaches is the need to emphasize equity as a core tenet of sustainability, especially in a socio-economic context of extreme inequality. The importance of equity to support sustainable sanitation service delivery in South African informal settlements was highlighted and a new perspective of different dimensions of equity in sanitation was a result of the research.

The South African government has taken strides to try and meet both international and domestic development goals with its Free Basic Sanitation policy, for which a national implementation strategy was developed in 2008.

This study focuses on technology application to address the limitation in technical options by developing a smart emergency toilet called eSOS (emergency sanitation operation system) Smart Toilet. This toilet is based on the eSOS concept that takes into account the entire sanitation chain. The initial design was built into an experimental toilet prototype, which was then evaluated under real usage in an emergency camp in Tacloban City, the Philippines. This field research in the Philippines aimed to evaluate various operational aspects of the toilet. These aspects were design related but the aim was also to obtain new knowledge as the result of the toilet’s sophisticated monitoring system. The field research evaluated the usage and operation, certain smart features, characterisation of the generated faecal sludge and urine streams, and the user acceptance. Furthermore the study focused on technology application to address the limited time for planning in emergencies by developing a decision support system (DSS) to select sanitation options. The aim is to enable users of the DSS to plan their emergency sanitation response within the shortest time possible. The outcome of using the tool that was developed is that it gives the highest rated sanitation system as the most suitable technical sanitation option in the users’ given scenario. The characteristics of the eSOS monitoring system, that can measure and track the material flows, gave the opportunity to estimate the costs of all the activities in one functioning sanitation chain. Cost components are usually missing in general sanitation planning. Often, the cost estimation is only provided for a single sanitation chain, instead of costs for the whole sanitation chain. The study developed a financial flow simulator called the eSOS Monitor to address this gap in sanitation chain cost estimation. The eSOS Monitor adopts the sanitation technology selection by the DSS and then calculates the costs for each chain. The cost summary then also calculates the most important financial indicators that are useful for parties interested in investing in the sanitation business. In general, the main objective of the study was to contribute to a better emergency sanitation response. The results were also applied to the development of decision support tools useful for applications beyond emergencies.

The eSOS concept has the potential to improve the sustainability of sanitation services through innovations at each component of the sanitation chain.

The Shit Killer is the invention of professors Brdjanovic and Mijatović and developed with support from the Bill & Melinda Gates Foundation and the Dutch government. It is primarily designed to sanitize fresh human excreta as well as to reduce the volume of faecal sludge. The technology can also be applied for the treatment of household septic sludge and waste activated sludge from sewage treatment plants. The device is based on the novel application of microwave-based technology that can deactivate the pathogenic microorganisms by generating heat inside the reactor, and by further thermal action, can reduce the volume of treated sludge. The Shit Killer has been tested in Slovenia and Kenya with promising results: the achieved content of dry solids was more than 90% and dried sludge was practically pathogen-free. The experimental system was further optimized, scaled up to a containerized pilot of 1,000 PE capacity and tested on the treatment of fresh excreta (urine and faeces) from mobile toilets, septic tank sludge, fresh waste sludge and dewatered sludge from local municipal wastewater treatment plants. After testing in Croatia and Slovenia the containerized system will be tested in a refugee camp in Jordan. It can be mobile or stationary and is a particularly suitable solution for small towns’ sludge treatment. Its envisaged application ranges from waste sludge treatment at municipal wastewater treatment plans to sanitation provision for non-sewered areas, refugee camps and urban slums.

The Shit Killer® is promising technology for the treatment of fresh faecal sludge, septic sludge and waste activated sludge, and particularly suitable for the onsite treatment of smaller settlements.

Low cost sanitation facilities such as urine-diverting dehydrating toilets (UDDT) have been adopted as an innovative solution to enhancing sanitation within informal urban slum settlements. This new approach to sanitation provision has posed numerous challenges in terms of treatment of human faeces. Sani-BioR© seeks to enhance sanitization of the waste as well as increasing methane yield. The system encompasses the anaerobic co-digestion of UDDT faeces and mixed organic market waste (MOMW) in a ratio of 4:1 in a two-stage reactor system. The principal involves utilization of the toxicity effect of non-dissociated volatile fatty acids for pathogen deactivation and the subsequent increase in methane production. The system provides a decentralized, cheap and affordable approach to UDDT waste treatment, in addition to being applied at any scale. The Sani-BioR© system has been tested at pilot scale using UDDT faeces collected from the Mukuru Kwa Njenga slum settlement, Nairobi, Kenya. Testing and modification of the system took nine months. Key parameters monitored during the test period include: E. coli removal and changes in volatile acid concentration. Interesting findings were achieved in relation to the performance of the system:

• 8.0 E. coli log removal was achieved from the methanogenic reactor, meeting the WHO’s standard of 1,000 CFU/100ml;
• The Sani-BioR© system achieved 221 ml CH4/ g VS added, 30 % higher than corresponding production in the single stage system.
• In the methanogenic reactor, 20% TVFA existed in non-dissociated form.
• E. coli removal Sani-BioR© was 60% higher than in the normal single stage system. A correlation was found between E. coli removal and non-dissociated VFA (ND-VFA), increasing with an increase in the ND-VFA fraction.
• The UDDTF/MOMW ratio used depends on the degree of sanitization required, increasing with an increase in the MOMW fraction. Optimal non-dissociated volatile fatty acids were depicted at UDDTF/MOMW in the ratio 1:1.

The Sani-BioR© system focuses on enhanced sanitization and methane production from faecal sludge in informal slum settlements, offering an entry point to waste recycling as a component of sustainable integrated sanitation.

Over recent decades there has been renewed interest in optimizing and innovating wastewater treatment technologies (WTTs) in sub-Saharan Africa. However, poor city-dwellers need low-cost, reliable WTTs that allow for the safe reuse of the effluent in the water-scarce context. This research focuses on the design and test of two options for domestic wastewater treatment in the warm, dry sub-Saharan Africa climate of Ouagadougou, Burkina Faso. The first option consisted of two-stage high-rate Anaerobic Reactors followed by a Baffled Pond (AR-BP) with recycled plastic media as a medium for attached growth. The second option included the same two-stage high-rate Anaerobic Reactors but followed them with wet-dry Sand Filters (AR-SF). The research was conducted on a pilot scale, by applying a design flow of 1 m3/d, which was later increased to 1.5 m3/d. After two years of operation:
• Significant differences in mean COD, BOD5 and TSS removal efficiencies were achieved in both systems: 79, 81 and 72%, respectively, for AR-BP and 84, 88 and 88 %, respectively, for AR-SF;
• The introduction of three vertical baffles increased the hydraulic retention time and decreased the dead volume in the BP. Thus, the hydrodynamics and the performance of the pond were improved, and the costs and the amount of land that is required were reduced;
• It was also found that high pathogen removal efficiencies were achieved in both the treatment options with 6 and 5 log units for AR-BP and AR-SF, respectively;
• The AR-SF option presented a high rate of nitrification, while the BP was more efficient in removing ammonia nitrogen (84 %) and E. coli (6 log units);
• The two-stage high-rate anaerobic reactors (R1 and R2) produced a significant amount of biogas, with 9.7 L/m2 per day of biogas and a methane content of 54 %;
• Very low sludge yields were recorded in R1, R2, and BP (0.0006, 0.0002 and 0.0014 m3/cap. yr, respectively), thus reducing the cost of its extraction and management.
The next step will focus on developing a prototype and testing it in a real situation as a semi-centralised system combined with simplified sewerage technology. Instead of using a fixed system, the idea is that the prototype would be prefabricated plastic, adjustable and portable and it could be applied in residential areas, small-scale communities, and emergency situations as well.

The two treatment options can be recommended as alternative low-cost wastewater treatment technologies for African cities, with the final effluent being used for restricted irrigation in peri-urban agriculture.

The solar septic tank is a modified conventional septic tank with solar-heated water. Operating the septic tank at temperatures higher than ambient conditions enhances pathogen die-off and produces better quality septic tank effluent, as well as reducing sludge accumulation by 50 %. The reduced accumulated sludge production lengthens the desludging period and saves costs in sludge management. The reduced sludge volume would minimize the pollution problems caused by unsanitary disposal of sludge practices in developing countries. The solar septic tank is designed to be used by up to 6-10 people (1-2 families) and offers the added benefit of turning waste into fuel and water that is reusable in agriculture. The solar septic tank system, which involves an advanced biochemical process, consists of three main components (i) a solar water heating device, (ii) a heat transfer pump and equipment and (iii) a modified septic tank. In order to increase the temperature inside the solar septic tank, hot water generated by the solar heating device is circulated through the heat transfer equipment by a pump. Currently, two solar septic tank units are in operation at the Asian Institute of Technology, Thailand, and one unit is installed and being monitored at the worker residence area, the Santavee factory, Samutphakarn Province, Thailand. The observation results show that the temperature inside the solar septic tanks can be increased up to the range of 45-50 oC (in the day time). The treatment efficiencies of organics/solids removal and E. coli inactivation were found to be about 70-90 % and 4-5 log reduction, respectively. Biogas production was 10-20 and methane gas is 70-80 L/d.

Solar thermal energy in the septic tank is considered an effective sanitation method for deactivating pathogens, converting organic wastes into methane biogas and alleviating the environmental concerns associated with fecal sludge handling.

To evaluate the potential of vermifiltration technology in treating concentrated greywater generated from urban poor, experiments were conducted from March 2013 to July 2015 in the 2iE foundation, Ouagadougou, Burkina Faso. From the experiments conducted, the following important results were obtained:
• This technology has the ability to treat pollutants in a single facility at household level;
• In all the experiments, average removal efficiencies of > 90% for BOD5 and TSS, 80-90% for COD, 60-70% for NH4, 40-50% for NO3, 50-60% for NO2 and PO4, and 1-4 log units for coliforms were achieved;
• The locally available earthworm, Eudrilus eugeniae, tolerated a temperature of 41.5 oC inside the filter.
• Fine sawdust can be used as a substitute for sand in vermifilters;
• The vermifilters used odour-free potential organic matter and earthworms that could be harvested every 6-8 months. The vermifilters no longer supported the earthworms’ growth after several months of operation;
• Major removal of pollutants was achieved by the sawdust layer (top layer with 30 cm depth) for most parameters.
• Higher numbers of bacteria were found in the vermifilter compared to the control unit, which may be associated with the presence of earthworms;
• The sawdust vermifilter performed slightly better compared to the cow dung vermifilter;
• Microbial communities are working with earthworms in pollutant removal as fungi, bacteria, and actinomycetes were identified in samples of filter materials at different depths;
• There were pH differences in the filter materials along the depth which might be caused by the chemical accumulation or precipitation, and the earthworms and microbial activities;
• The bacterial distribution in the vermifilters and the control unit were higher at the top compared to the bottom.
The results are encouraging but need to be tested at household level by scaling up the prototype.

Vermifiltration technology constructed from locally available materials and using locally available earthworms is a feasible option to treat concentrated greywater generated from urban poor.

This research generated the innovative business model of faecal sludge collection and transport services (FSCTS) and proposed appropriate business solutions to support the business decision-making process. The nine business components and two external components make up part of this model. Service performance indicators include, but are not limited to, five indicators: financial results, customer satisfaction, corporate social responsibility, an environmental code of conduct and service efficiency. The ownership status of a service organization affects the operating cost and profit of FSCTS. In Thailand and Vietnam, all the surveyed private services have positive financial results while public services have negative results. Privatization is a trend to secure a profit for FSCTS. This business model is proposed as one of the applicable benchmarking tools for service providers to examine their current business and service models. When service providers have not organized their services with a well-defined model, they can refer to our proposed business models. When service providers have their own business model concept, they can use our proposed business model to compare to and develop their business. Field testing in Vietnam indicated that four possible solutions could be applied and prototyped there, including improved transport vehicles, the logistics planning tool, a cooperative model for Vietnam market, and environmental–friendly branding, as a business solution to make FSCTS more reliable, profitable and environmentally friendly.

Our business model is proposed as one of the applicable benchmarking tools for service providers to evaluate their current business and service practices.

The performance of pit latrines was investigated in 9 different slums of Kampala, Uganda. 130 pit latrines were assessed to determine the status of pit latrine structures, and their influence on performance. 42 pit latrines were investigated to establish the relationship between pit environmental conditions and their performance. Additionally, laboratory experiments were carried out to demonstrate the potential of indigenous microorganisms (IMOs) in improving the performance of pit latrines. The results from the different studies on the performance of pit latrines presented the following findings;
• 51% of the latrines were full and 15% overflowing, 39% had a strong malodorous smell with a few flies in 80% of the latrines. 43% of the latrines were dirty. 89% of users wanted to improve their pit latrines. The ventilated improved pit (VIP) latrines did not perform (smell, flies) better than simple pit latrines.
• Predictors of pit filling were signs of rain or storm water entry (β = 34.6), flooding (β = 5.3), and cleaning time (β = 5.0). Cleanliness (β = 97.6), stance length (β = 1.0), superstructure material (β = 0.01), use by households only (β = 0.01) and cleaning before/after use (β = 0.02) were predictors of smell. The presence of flies was related to superstructure material (β = 70.6).
• An assessment of the environmental conditions found low wind speeds (0-0.6m/s), pit temperature (21 to 30.7 oC), pH (5.0 – 11.8) and ORP (-247 to 65.9mV).
• Pit content was anoxic (ORP < + 50mV) pits, in the acid formation range (ORP -199 to -51mV). Smelling pit latrines and flies were within the acid formation ORP range. There was a significant association (G=0.797, p=0.014) between ORP and smell in only clean latrines, implying changes in pit environment would affect only smell.
• Following the laboratory, degradation experiments of faecal matter and IMOs, only faecal matter load affected mass reduction (indicator of filling). Ammonia concentration (indictor of smell) was affected by faecal matter load, IMO application and interaction of IMOs. Maximum IMO3 application was 1,300 g at a faecal load of 16,000 g, implying application twice a week.

Pit latrine performance (filling, smell and insects) is influenced by a number of factors, including the status (design, construction, operation and maintenance), and environmental conditions.

Biofil Toilet Technology (BTT) is a household blackwater treatment unit that has been developed to mitigate issues such as limited land space for toilet facilities; lack of access to desludge traditional toilets in complicated layouts; long haulage to huge treatment systems for final disposal of waste, and odour problems. Laboratory-scale soil columns and miniature BTTs were used for the testing. Feeds, effluent from existing BTTS and fresh faeces from households were used. Some of the key data and results indicate the following:
• From four different soil columns, laterite and sand were found to have a high efficacy for COD, BOD5, and TSS with up to 80% of all contaminants being removed at a depth of 0.3 m in the soil column.
• A two to five log pathogen removal was recorded for the soil columns.
• GR, SP and PKS particle sizes were uniformly graded and similar, and thus could be substituted in their use as pervious composites for separation in blackwater treatment.
• The permeability of the composites was heavily influenced by their densities.
• The mean pH in the effluent filtered through the composites was higher than in the influent, most likely the result of the available calcium carbonate in the cement.
• The pervious composite was not consistent in terms of N removal but was for P.
• SP was the only composite effective in removing E. coli.
• Worms reacted to the chemical application by moving away from the point of application.
• Aqueous solutions of chloroxylenol, hydrogen chloride and sodium hypochlorite exhibited paralyses and caused deaths of up to 40 % of earthworms, especially at higher concentrations of 2.0 g/100mL and 3.0 g/100mL.
• The concentration of 3.0 g/100mL is statistically likely to kill 50 % of the population of worms.
The results favour the use of alternative materials to reduce the cost of production and transport for its components. They also suggest good options for effluent treatment in areas with a high water table or clayey soils. Furthermore, cleaning with household chemicals does not compromise the functionality of the BTT due to the dilution factor, unless abused.

The Biofil Toilet is a novel on-site vermi-biofiltration technology designed and developed in Ghana to service a wide spread of users.

A natural wastewater treatment line was implemented to treat raw sewage in Brazil, using a total area of 1.5 m2/cap., while maintaining high removal efficiencies for the major constituents. In order to reduce the required area, an upflow anaerobic sludge blanket (UASB) reactor, a pond without baffles followed by another shallow pond with baffles was proposed. A rock filter with three decreasing grain sizes was also incorporated into the system after the ponds in series to remove the remaining particulate organic matter from the ponds, while avoiding clogging because of the decreasing grain size. The system was designed to treat sewage from 250 inhabitants. During the 2 years and 3 months of operation, the following conclusions were reached:
• High overall organic matter removal (BOD = 93%, COD = 79% and SS = 87%), limited TKN (55%) and ammonia-N (43%) removal, and excellent removal of total coliforms (5.9 log units) and E. coli (6.1 log units) at low treatment time (6.7 days );
• The final effluent complied (100%) with all three standards (BOD, COD, SS) set by the Official Journal of the European Communities No. L 135/40 for discharging stabilisation pond effluent;
• This suggests that this system can be used not only in developing countries, but that it is also suitable for developed countries with warm climate.. The final effluent qualified for two different practices of unrestricted irrigation and three practices of restricted irrigation following WHO (2006) guidelines. Unrestricted irrigation: suitable for irrigation of non-root salad crops (e.g. lettuce, cabbage) and vegetables eaten uncooked; and drip irrigation of high-growing crops (such as fruit trees, olives). Restricted irrigation: labour-intensive restricted irrigation; restricted irrigation using highly mechanised agricultural practices (e.g. tractors, automatic sprinklers, etc.); subsurface irrigation via the soil absorption system.

A combined solution of a UASB reactor, two maturation ponds (unbaffled and baffled) and a granular rock filter operating in series to produce an effluent compatible with different discharge conditions and irrigation practices with a retention time of less than seven days.

Swamp areas are mostly formed either as a tidal swamp because of the tidal effect of being near coastal areas, estuaries and other areas that are affected by tidal waves, or as a non-tidal inland swamp in flat areas near to lakes, rivers or other areas with no rainwater runoff. They are indicated as areas with soft soil where the soil is permanently filled with water, and are mostly affected by seasonally inundated conditions. In some South East Asian countries, many swamp areas are used as residential areas. Providing wastewater treatment systems for human settlements in swamp areas is challenging, both from technical and non-technical aspects. Therefore, this research is conducted to achieve a better understanding of the problem of providing appropriate wastewater treatment technology to fit the specific conditions of swamps and to meet the requirements of swamp communities. The selected wastewater treatment technology considered to be applied in South Sumatera was the Tripikon-S system, a modification of the septic tank system using a PVC pipe as the container. The strength of this system is related to the limited land area required, watertight material, its placement that can minimize soil-related problems, and the placement of an outlet that can prevent the backflow while there are inundated conditions. In order to enhance the performance, two modifications were made, namely: the addition of a bioball as attachment media, and the addition of a venturi-shaped chamber to get air into the system. The results show that with influent organic matter of 1,500-2,000 mg/L COD, 48 hours of retention is preferable. Under such operation, 50-62 % COD removal was achieved by the original Tripikon-S design, 64-66 % with the bioball addition, and 65-67 % with the venturi chamber. These promising results show that the modified tripikon-S system has the potential to be applied for removal of COD in the swamp communities of Indonesia. With a good understanding of the social and physical environmental conditions of river swamps and estuary swamp settlements, along with the promising laboratory results of the tripikon-S system, an integrated strategy for applying wastewater treatment infrastructure to meet the needs of swamp communities has been developed in this research, also covering construction and management strategies.

Provision of wastewater infrastructure to urban settlements in river and estuary swamp areas can be addressed with deeper insight and more confidence using the results of this research.

Technologies for decentralized management of faecal sludge (FS) are costly, and therefore reduction of volume of FS is both needed and welcome. Dewatering experiments were performed on FS obtained from latrines in three slums in Kampala (Uganda). A lot of interesting and novel data has been obtained, such as:
• The dewatering rate of FS from lined pit latrines was not significantly different from that of unlined pit latrines (CST=1,122 s and 1,485 s, respectively);
• The dewatering extent of FS from unlined pits (31.8 %) was higher than that from lined (18.6 % cake solids);
• the dewatering extent of FS from lined pits decreased with increasing volatile solids and increased with increased sand content;
• The change in particle size proportions had no effect on the dewatering extent of FS;
• The application of physical conditioners (sawdust and charcoal dust) commonly found in Kampala slums improved the dewaterability of FS from lined pits;
• the sawdust dosage of 75 % FS solids improved the dewatering rate and dewatering extent of FS by 14.3 and 22.9%;
• Similarly, a 75 % dosage of charcoal dust improved the dewatering rate and extent by 15.8 and 35.7 %;
• Also, a 50 % dosage of sawdust and charcoal dust increased the calorific value of FS by 42 and 49 %;
• The FS cake structure became porous after the addition of sawdust and charcoal dust. Moreover, such porous FS is much easier to dry and compost;
• The centrifugation conditions of rotational speed, time and FS volume were optimized using a laboratory centrifuge;
• The rotational speed of centrifuge was a key parameter in dewatering of FS conditioned with saw- and charcoal dust;
• 20 min was the maximum time for batch centrifugation, beyond which cake solids reduced;
• Charcoal dust showed better results in dewatering extent (higher cake solids) than sawdust under similar centrifugation conditions.
The results showed that centrifugation technology can be further explored through prototype design, manufacture and testing for potential scaling up.

Dewatering faecal sludge presents an important step for resource recovery, thus incentivizing its management to bear its own cost, leading to improved public health and environmental protection in urban slums.

Case studies from three informal settlements in Cape Town, South Africa show that what matters and affects users most is if sanitation technologies fail to meet the users’ fundamental human needs for safety from physical and emotional harm (security), comfort, good ventilation, cleanliness, accessibility (day and night), consistent and adequately supported O&M, and dignity. International, national, provincial and local governments all use the WHO indicator of number-of-toilets-to-people ratio to ascertain sanitation provision progress. However, these indicators fail to consider human experiential factors such as those of Cabisa (a pseudonym), a respondent in a Cape Town informal settlement, who was raped and physically assaulted in a toilet facility that fits on the top rung of the WHO’s sanitation ladder. Yet it failed to provide a security function such as is necessary in most informal South African settlements. The study recommends a function-based indicator as an alternative (or complement) to the ineffective WHO’s technology-based indicators of progress on sanitation provision. Also presented is previously undocumented evidence of sanitation users’ experiences i.e. everyday practices, challenges and opportunities, as well as knowledge about user and settlement characteristics in three informal settlements in Khayelitsha, Cape Town. Sanitation provision is a process that includes a series of interrelated principles, standards (based on a ‘limited-resources’ ideology), beliefs, practices and artifacts – all applied in a human and natural environment to create and sustain public health and improve overall human wellbeing. The most effective approach to such provision is to serve the social, health and environmental functions that are based on the users’ environment, practices and expectations. Consequently, function-based indicators of sanitation progress must complement the WHO’s indicators.

The extent to which those global sanitation goals have been met, especially in informal settlements, has commonly been assessed statistically using ratios such as numbers of toilets per population size. Such assessments fail to account for informal settlement residents’ expectations, how they use and manage the toilets that local authorities provide, and the reasons for the challenges faced by those authorities in maintaining such facilities.

Survey of nineteen biogas latrines was undertaken in informal settlements of Kampala and Nairobi to determine performance of biogas latrines indicated by the number of burning hours in a day and users satisfaction. The findings of the study showed that:

• Performance of the biogas latrines is mainly influenced by skills of masons responsible for their construction, use of standards in construction, training of users on operation and maintenance aspects of the biogas latrines, number of users and their motivation in installation of the biogas latrines ;
• Co-digestion of human excreta and cow dung increased the performance in terms of number of burning hours in a day from 0.5 to 1.1;
• Temperature in the digesters of biogas latrines was within mesophilic range (25 0C to 45 0C) for anaerobic digestion process;
• pH was within 7.6 – 8.4;
• Volatile fatty acids were in the range of 5-8.3 mg/L;
• Oxidation reduction potential ranged from -100-56 mV ;
• Moisture content was > 90% and total solids correspondingly < 10%.
• Carbon to nitrogen ratio of the substrates was 2:1 for human excreta and 6:1 for a combination of human excreta and cow dung. Co-digestion of human excreta and cow-dung resulted in more biogas production than in case of use of single substrate.
• Biogas flow rate ranged from 0.24 to 0.58 m3/h while methane content was 57-63 %;
• Performance of biogas latrines is influenced by a combination of the operating conditions of temperature, pH, volatile fatty acids and carbon to nitrogen ratio of the substrate and hence their monitoring and anaerobic digestion process control to optimal conditions are key.
• There was only limited reduction of E.coli by 0.86-1.6 log10, Salmonella spp. by 1.03-1.92 log10, total coliforms by 0.66-2.02 log10, Enterococcus spp. by 1.26-2.74 log10, Ascaris eggs by 0.25-0.41 log10 units.

The biogas latrine is an integrated waste management system that provides a sanitation solution as well as energy in form of biogas and is suited for use in urban informal settlements.

In Ghana, faecal sludge treatment is only available in four big cities. This study therefore sought to investigate the performance of a rotary drum composter in the destruction of helminths (Ascaris and Trichuris eggs). A rotary drum composter with a volume of 75 L was used for the composting at the laboratory scale. The composter was fabricated with a plastic and galvanized metal sheet of 5 mm thickness and was batch operated. The main units of the composter are the drum (metal and plastic) and a mixer (rotating paddle/baffle). Five complete rotations of the drum were manually carried out on the first day and subsequently every three days for the first three weeks and afterwards every 10 days until the end of the composting process. Composting with the rotary drums revealed some interesting results, such as:
• The study found that all the compost feedstock (faecal sludge and shredded corn cobs) samples analyzed were infected with Ascaris and Trichuris eggs, with Ascaris being more prevalent;
• The temperatures generated within the rotary drums (54-62 oC) were sufficient to enable a high removal rate of Ascaris and Trichuris at the end of the composting process;
• The die-off of Ascaris and Trichuris at the end of the compost process was statistically significant (p<0.0001) when compared with their initial concentrations;
• It was seen that the viability of the counted Ascaris and Trichuris eggs decreased during the course of the composting process;
• Composting of raw faecal sludge and shredded corn cobs using a rotary drum is an effective means of reducing the Ascaris and Trichuris population in faecal sludge intended for agricultural use as an organic fertilizer.
The rotary drum composter is an efficient and promising technology to treat faecal sludge at the household level in peri-urban and rural areas. This technology will be used to turn the compost in the vaults of the latrine which previously involved manual turning with a shovel. Overall the rotary drum technology will reduce the cost of hauling faecal sludge over long distances to treatment sites and also significantly reduce human contact with faeces, thus improving public health.

The rotary drum composter has demonstrated that it is an efficient and promising technology to treat faecal sludge at the household level.

Characterizing odour only at source is not sufficient to account for the effective impact of odours on citizens, which would require quantifying odours directly at the receptors. This is one of the main reasons for the spreading of odour impact assessment approaches based on odour dispersion modelling. Because of the assumption that single odorous compounds may be insufficient to account for effective odour perception, the possibility of measuring odours in the field, both as a way of directly assessing odour annoyance and of verifying that the modelled odour concentrations correspond to the effective odour perception by humans, is the main objective of this research. The purpose of this research was to apply field olfactometry methods to measure odour from dry onsite toilet facilities in an urban-poor area. This method was used to confirm an odour perception survey carried out in the vicinity of the facility. The key features of this process include the selection of field measurement panelists – nasal chemosensory performance, odor strength measurement and the collection of GPS and weather data. The odour monitoring coupled with the modelling studies revealed some interesting results as follows:
• the results generally showed how subjectivity could be reduced by the so-called ‘calibration of the human nose’ for objective field measurements and how it can be used alongside perception survey and modeling;
• they also show the applicability of the Gaussian Study state plume model to model the dispersion of odor from a communal toilet facility;
• they confirmed the perception of why odor is most intense in the morning as compared to other parts of the day;
• they show that an increase in the release height (height of the vent pipe) can reduce the ground-level odor perception, and;
• they again show how reduction in odor strength at source can reduce ground-level odor concentration.
As a first attempt at objective field measurement of odour from dry onsite communal toilet facilities using humans as assessors, the methods could be replicated at other sites and this could lead to the formulation of legislation on odour nuisance, which is not available currently.

This approach presents the first attempt at objective monitoring of odor from dry onsite communal toilets in urban-poor Ghana using the Nasal Ranger Field Olfactometer®.

Hydrothermal carbonization (HTC) is a thermal conversion process which can be applied to treat faecal sludge (FS) and convert it into a valuable solid product called hydrochar. Experimental results of the HTC process indicate the significance of moisture content on the energy content of the produced hydrochar. Likewise, increasing temperatures and reaction times result in increased energy contents of the produced hydrochar. Optimum conditions of the HTC of FS to produce the highest normalized energy yield are a moisture content of 80 %, reaction time of 5 h and temperature of 250 C. In these conditions, the energy content and hydrochar yield are 19-20 MJ/kg and 70-73%, respectively. The energy content of the produced hydrochar can be further increased by adding either a catalyst or biomass such as acetic acid and cassava pulp, respectively. A low-energy HTC process named ‘Two-stage HTC’ comprising of hydrolysis and carbonization stages using FS as feedstock has been developed. Optimum conditions for the two-stage HTC of FS are a hydrolysis temperature of 170 C, hydrolysis reaction time of 155 min, carbonization temperature of 215 C, and carbonization reaction time of 100 min. In these conditions, the energy content and hydrochar yield of 20-21 MJ/kg and 70-73 %, respectively, can be achieved. The energy required for the two-stage HTC is approximately 25 % lower than the conventional HTC process. Characteristics of HTC products including hydrochar, liquid and gas products have been identified. The ranges of the energy content of the produced hydrochar are comparable to natural coals. Thus, it can be considered for use as a solid fuel in typical combustion processes. Other potential applications of the produced hydrochar based on its characteristics could be an anode in a Li-ion battery, and an absorbent in water purification. The experimental results obtained from this study using a lab-scale HTC reactor show the technical feasibility of the HTC process to treat FS and produce hydrochar which can be utilized as valuable products such as solid fuel, an adsorbent of toxic chemicals and an anode in batteries, and which minimize public health risks and environmental problems. Also, selling the generated products such as hydrochar could cover the collection, transport and treatment costs.

The hydrothermal carbonization process can be applied to treat faecal sludge and produce hydrochar, which can be used as a solid fuel, and other value-added products.

Unfortunately, the sanitation products that are currently used during emergencies are unable to achieve proper sanitation or to prevent disease. The innovation of products to find and scale solutions to emergency sanitation is of vital importance, but with little understanding of the process, the emergency sanitation sector is unable to identify whether and how the product development process should be improved. Interviews and surveys with customers, suppliers, and product developers, as well as case studies in Indonesia and the Philippines that involved end users, have been carried out to provide a detailed understanding of the process of developing an emergency sanitation product. By analysing the context, characteristics and role of end users, support provided to suppliers and product developers, barriers and enabling factors through the product development process, the findings suggest that there are many areas for improving product development in the emergency sanitation sector. For example, one critical area for improvement is inadequate design requirements. A problem analysis of the research findings found that inadequate design requirements is caused by three factors: (1) overlooking aspects of the solution; (2) poor understanding of design requirements by suppliers and product developers, and; (3) poor definition of design requirements. The consequence is that ideas that are generated from these inadequate design requirements may not successfully progress to an end product or fail during implementation. This is because the ideas only address part of the problem or do not reflect the actual needs and constraints of the stakeholders. Activities that can be implemented to overcome these problems include fostering interaction between stakeholders, building knowledge and skills through training and proper data collection, leveraging the expertise and skills of qualified persons, and utilising relevant tools. The necessary funding and resources must be made available to implement these activities. Overall, this research represents a first analysis of the product development process in the emergency sanitation sector. The findings offer a basis for decision makers to improve innovation in the emergency sanitation sector. From the analysis, decision makers will be able to analyse and choose from the alternative solutions to develop programs and projects to improve product development in the emergency sanitation sector.

In-depth research into how emergency sanitation products are developed highlights critical barriers to product development in the sector, and offers insights into how innovation could be improved.

The research facility at UFMG is comprised of a typical first stage of the French system of vertical wetlands, built according to the specifications and recommendations of CEMAGREF/Irstea. Initially, the system was built to treat only domestic sewage for approximately 100 population equivalents but lately the system has also started treating septic tank sludge. The units were planted with Tifton 85 (Cynodon ssp). Each of the three units was 3.1 m wide and 9.4 m long, leading to a total area of 87 m² (approximately 0.9 m²/capita). During the monitoring period only 2/3 of the area (two units) was taken by the traditional first stage of the French system to treat domestic sewage, while the third unit was dedicated to septic tank sludge. Each sewage unit was fed for 7 days and rested for 7 days. Trucks transporting septic tank sludge discharged each week onto the sludge unit and then the percolate was sent to the post-treatment unit. Different operational conditions of the system treating septic tank sludge were implemented, including retention of the percolate for 7 days and for 14 days respectively. After three years of operation using vertical flow constructed wetland (VFCW) for domestic sewage and septic sludge treatment, the following aspects can be concluded:
• Satisfactory organic matter and total suspended solids removal (BOD = 93%, COD = 79% and TSS = 87%);
• Good TKN (63%) and ammonia-N (49%) removal;
• The presence of the plants Cynodon dactylon pers prevented the VFCW from clogging;
• The utilization of only the first stage of the French/CEMAGREF systems shows a large potential whenever simple systems are required for the treatment of raw domestic sewage in developing countries and regions with a warm climate;
• Treating septic tank sludge with retention of the percolate for 7 days in the sludge unit followed by sending the percolate for retention during 7 days in the post-treatment unit was found as the best alternative, leading to global median removal efficiencies of 90% for BOD, 94% for COD, 68% for TS, 80% for TVS, 68% for ammonia-N, 87% for TKN and 99.98% for E. coli;
• The dewatering of the accumulated sludge worked well, producing a top sludge with 55% of dry solids and a TVS/TS ratio of 60%;
• The system showed to be robust in regard to different types of septic tank sludge, hydraulic loading rate and solids loading rates.

The use of vertical flow constructed wetlands (VFCW) for domestic sewage and septic tank sludge treatment has shown promising results and appears to be a solution for low-cost treatment and decentralized sanitation.